A uniform resource identifier (URI) of an electronic document, such as a landing page, can be assigned to or inserted in a respective third-party content item presented on client devices. The electronic document associated with the URI can provide information related to the respective third-party content item or the third-party content provider thereof. Upon actuation of a URI, a client device can interact with the content associated with that URI, for example, by clicking interactive items therein, executing an online transaction, downloading or uploading content, actuating a video segment, or inputting text in a text field. Monitoring such client device interactions can allow third-party content providers to assess the success rate of respective third-party content items in engaging client devices.